Increased Foxp3+Helios+ Regulatory T Cells and Decreased Acute Graft-versus-Host Disease after Allogeneic Bone Marrow Transplantation in Patients Receiving Sirolimus and RGI-2001, an Activator of Invariant Natural Killer T Cells.

Regulatory T (Treg) cells play a central role in immune tolerance and prevention of aberrant immune responses. Several studies have suggested that the risk of graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT) can be ameliorated by increasing Tregs. We have developed an approach of in vivo expansion of Tregs with RGI-2001, a novel liposomal formulation of a synthetic derivative of alpha-galactosylceramide, a naturally occurring ligand that binds to CD1 and activates and expands invariant natural killer cells. In preclinical studies, a single intravenous infusion of RGI-2001 expanded Treg and could ameliorate GVHD in a mouse model of allogeneic HCT. To explore the role of RGI-2001 in clinical HCT, we initiated a phase 2A clinical trial (n = 29), testing 2 different doses of RGI-2001 administered as a single infusion on day 0 of allogeneic HCT. RGI-2001 was well tolerated and without infusion reactions or cytokine release syndrome. A subset of patients (8 of 29, 28%) responded to RGI-2001 by inducing a markedly increased number of cells with a Treg phenotype. The Treg had a high Ki-67 index and were almost exclusively Helios+ and Foxp3+, indicating that their accumulation was due to expansion of natural Treg. Notably, the incidence of grade 2 to 4 GVHD in the 8 patients who responded to RGI-2001 was 12.5%, compared with 52.4% in the 21 patients who did not respond. No grade 3 or 4 GVHD was observed in the responder group, compared with a 9.5% incidence among nonresponders. Immunosuppression with sirolimus was also associated with a low incidence of GVHD, suggesting that RGI-2001 may have synergized with sirolimus to promote Treg expansion.

Single and multiple dose MultiStem (multipotent adult progenitor cell) therapy prophylaxis of acute graft-versus-host disease in myeloablative allogeneic hematopoietic cell transplantation: a phase 1 trial.

We conducted a multicenter, phase 1 dose escalation study evaluating the safety of the allogeneic multipotent adult progenitor cell (MAPC, MultiStem, Athersys, Inc., Cleveland, OH) stromal product administered as an adjunct therapy to 36 patients after myeloablative allogeneic hematopoietic cell transplantation (HCT). Patients received increasing doses of MAPC (1, 5, or 10 million cells per kilogram recipient weight) as a single i.v. dose on day +2 after HCT (n = 18), or once weekly for up to 5 doses (1 or 5 million cells per kilogram; n = 18). Infusional and regimen-related toxicities were assessed for 30 days after the last MAPC dose. Of 36 allogeneic HCT donors (17 related and 19 unrelated), 35 were 6/6 HLA matched. MAPC infusions were well tolerated without associated infusional toxicity, graft failure, or increased incidence of infection. Median times to neutrophil (n = 36) and platelet (n = 31) engraftment were 15 (range, 11 to 25) and 16 (range, 11 to 41) days, respectively. The overall cumulative incidences of grades II to IV and III and IV acute graft-versus-host disease (GVHD) at day 100 were 37% and 14%, respectively (n = 36). In the group that received the highest single MAPC dose (10 million cells/kg), day 100 incidence of grade II to IV GVHD was 11.1% (1 of 9) with no observed cases of grade III and IV GVHD. We found no evidence for MHC class II allogeneic antibody induction, although some patients showed an increase in serum anticlass I titers compared with baseline. MAPC contribution to blood chimerism was negligible. These phase I data support the safety of stromal stem cell therapy and suggest that MAPC should be tested prospectively as a novel therapeutic option for GVHD prophylaxis after HCT.

Budget impact analysis of belumosudil for chronic graft-versus-host disease treatment in the United States.

AIMS: To assess the impact of belumosudil on the cost of care in chronic graft-versus-host disease (cGVHD) patients who have failed at least two prior lines of systemic therapy using a budget impact model. METHODS: A budget impact model with a 5-year time horizon was constructed in Microsoft Excel. The base case model uses the US prevalence rate of 3 L/4L + cGVHD patients from literature and secondary sources, with the potential for user-defined inputs, including model perspectives. The model includes data for two perspectives: the national US population and a hypothetical US private payer health insurance plan with 10 million (Mil) members. Additional model inputs include market share of cGVHD treatments, their associated adverse event rates, and healthcare resource utilization. RESULTS: The potential annual budget impact for the US national and payer plans was evaluated for cGVHD patients. Based on belumosudil utilization increasing to 55% in 3 L and 4 L + by 2026, cost savings of ∼5.5% and 6.7% ($128.8 and $4.9 Mil USD) were observed from national and payer perspectives, respectively. Cost savings in 2026 were derived from fewer AEs ($108.4 and $3.9 Mil USD, for national and payer perspectives; e.g. neutropenia, and thrombocytopenia) and reduced HCRU ($65.1 and $2.3 Mil USD, for national and payer perspectives; e.g. emergency room visits, ICU stays, etc.). LIMITATIONS: Results from the model were dependent on the available data inputs and assumptions. Real-world values may differ from the assumed performance of treatments, market growth, and treatment dosing and duration. CONCLUSION: The model results suggest that the introduction of belumosudil to treat cGVHD would be associated with substantial cost savings when evaluating a scenario with versus without belumosudil from a US payer perspective.

Epidemiology and Treatment of Chronic Graft-versus-Host Disease Post-Allogeneic Hematopoietic Cell Transplantation: A US Claims Analysis.

Chronic graft-versus-host disease (cGVHD) is a complication of hematopoietic cell transplantation (HCT). Although the clinical outcomes of cGVHD are well documented, few studies have assessed treatment practices outside of clinical trials. The present study aimed to quantify the prevalence of cGVHD, examine provider prescribing patterns, and evaluate the healthcare cost and resource utilization (HCRU) in a US cGVHD population. We analyzed anonymized claims from the Medicare Fee-for-Service (FFS) 5% sample for beneficiaries enrolled between 2013 and 2016 and PharMetrics commercial 2013 to 2018 databases to identify cGVHD in allogeneic HCT recipients. cGVHD was identified based on International Classification of Diseases Ninth/Tenth Revision diagnosis codes for cGVHD or unspecified GVHD with a first diagnosis >180 days post-HCT or a maintained unspecified GVHD diagnosis for >12 months postindex of unspecified GVHD diagnosis. Longitudinal and line of therapy (LOT) analyses were based on the PharMetrics dataset for 2013 to 2018. Healthcare costs were calculated by adding the inpatient, outpatient, and pharmacy insurer and beneficiary paid amounts for the commercially insured population. Total HCRU was assessed using the number of inpatient and outpatient visits following the initial cGVHD diagnosis. In 2016, the projected prevalence of cGVHD in the United States based on the Medicare FFS and PharMetrics commercial databases was 14,017 individual patients. Within 3 years after undergoing allogeneic HCT, 42% of patients developed cGVHD; 66% of the cGVHD patients had a prior diagnosis of acute GVHD. The majority of cGVHD patients received at least one systemic therapy; 71% and 47% of cGVHD patients progressed to a second and third LOT, respectively. A total of 24 unique therapeutic agents and more than 150 combinations were used in the second and third LOTs. Corticosteroids and corticosteroid combination therapy were the most common forms of treatment across all examined LOTs. Furthermore, the most commonly used agents in the first LOT, second LOT, and third LOT were corticosteroids only, calcineurin inhibitors only, and corticosteroids only, respectively. In the 12 months postdiagnosis, cGVHD patients had an average of 21.0 cGVHD-related inpatient and outpatient visits (2.8 inpatient and 18.2 outpatient visits). A significant proportion of allogeneic HCT recipients continue to develop cGVHD, and despite advances in the understanding of cGVHD, corticosteroids remain the mainstay of therapy. Patients often progress beyond the first LOT, at which time the utilization of systemic therapies is highly variable, demonstrating the need for evidence-based treatment approaches.

ROCK2 Inhibition With Belumosudil (KD025) for the Treatment of Chronic Graft-Versus-Host Disease.

PURPOSE: The rho-associated coiled-coil-containing protein kinase-2 (ROCK2) signaling pathway regulates the Th17/regulatory T cells balance and controls profibrotic pathways. Selective ROCK2 inhibition with belumosudil (KD025) may offer a novel approach to the management of chronic graft-versus-host disease (cGVHD). PATIENTS AND METHODS: A phase IIa, open-label, dose-finding study of belumosudil enrolled 54 patients with cGVHD who had received one to three prior lines of therapy (LOTs). The primary end point was overall response rate (ORR). RESULTS: The median time from cGVHD diagnosis to enrollment was 20 months. Seventy-eight percent of patients had severe cGVHD, 50% had ≥ 4 organs involved, 73% had cGVHD refractory to their last LOT, and 50% had received ≥ 3 prior LOTs. With an overall median follow-up of 29 months, the ORR (95% CI) with belumosudil 200 mg once daily, 200 mg twice daily, and 400 mg once daily was 65% (38% to 86%), 69% (41% to 89%), and 62% (38% to 82%), respectively. Responses were clinically meaningful, with a median duration of response of 35 weeks, and were associated with quality-of-life improvements and corticosteroid (CS) dose reductions. CS treatment was discontinued in 19% of patients. The failure-free survival rate was 76% (62% to 85%) and 47% (33% to 60%) at 6 and 12 months, respectively. The 2-year overall survival rate was 82% (69% to 90%). Belumosudil was well-tolerated, with low rates of cytopenia. There were no unexpected adverse events and no apparent increased risk of infection, including cytomegalovirus infection and reactivation. CONCLUSION: Belumosudil treatment resulted in a high ORR and overall survival rate and demonstrated quality-of-life improvements, CS dose reductions, and limited toxicity. Data from the study indicated that belumosudil may prove to be an effective therapy for patients with treatment-refractory cGVHD.

Endpoints for clinical trials testing treatment of acute graft-versus-host disease: a joint statement.

Currently, no agents are approved by the United States Food and Drug Administration (FDA) for either prevention or treatment of acute graft-versus-host disease (aGVHD). Formal precedents establishing a comparative basis for assessing the efficacy and safety of new investigational agents are still lacking. As a step toward addressing this problem, a panel of experts met on 2 occasions to reach consensus on recommendations for terminology describing a clinically meaningful primary endpoint in studies assessing treatment for aGVHD. The panel recommended terminology for "very good partial response" (VGPR) that includes both diagnostic and functional criteria. The central hypothesis leading to this proposal is that the potential harm of giving more treatment than needed to produce or maintain complete response exceeds the harm of slight undertreatment that may be associated with less than complete response. VGPR clearly cannot be used as the sole outcome measure in GVHD treatment trials, and must be considered in the context of survival and safety. The proposed use of VGPR as the primary endpoint in GVHD treatment trials will remain provisional until its use has been validated through experience.